Adducts of zinc compounds and lubricants containing same



United States Patent 3 301 782 ADDUCTS OF ZINC COMPOUNDS AND LUBRI- CANTS CONTAINING SAME Edwin C. Knowles, Poughkeepsie, and Frederic C.

McCoy, Beacon, N.Y., assignors to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 9, 1963, Ser. No. 314,886

13 Claims. (Cl.- 25246.4)

bricating conditions are commonly encountered in the lubrication of heavily loaded pinion and spur gears, gear trains, bearings, extrusion applications and the like. As a result, there is an increasing need for lubricating compositions having improved properties for these services.

A novel class of oil-soluble amine or Schiif base adducts of zinc compounds has been discovered which imparts greatly improved properties to lubricating oils. The lubricant compositions containing the adducts are particularly notable. for their improvement in load carrying and anti-scuff properties although they also exhibit addition-aladvantages in corrosion resistance, oxidation resistance and stability. These lubricating compositions provide the answer to some heretofore diflicult lubrication problems. I

The novel oil-soluble adduct of the invention is formed from the reaction of an amine or a Schiff base and Zinc silicofiuoride, phosphate, hypophosphite, sulfite or thiocyanate. More particularly, the. adduct of the invention is represented by one of the following formulas:

(a),. I I

-(RR2N) X and R"N=oR' ,.X in which R is-a hydrocarbyl radical having from 6 to 30 carbon atoms, R 'is selected from the group consisting of hydrogen and a hydrocarbyl radical having from 1 to 30 carbon atoms,.R is an aliphatic radical having from 1 to 30 carbon atoms, the sum of the carbon atoms in either of the compounds represented byv (a) and (b) being at least 12, y is an integer from 1 to 6 and X is a zinc compound selected from the group consisting of zinc silicofluoride, zinc phosphite, zinc hypophosphite, zinc sulfite and zinc thiocyanate. 1

Amines which can, be employed to prepare the adduct 'of the invention are the amines having one or more hydrocarbyl radicals'in which the total number of carbon atoms in said amine is at least 12. The requirement of 12 carbon atoms in the amine is critical to insure the oil solubility of the adduct. Adducts formed from amines having less than 12 carbon atoms are generally not soluble in lubricating oils. The effective amines correspond to the formula:

- RR N wherein R is a hydrocarbyl radical having from 6 to 30 carbon atoms and R is hydrogen or a hydrocarbyl radical having from 1 to 30 carbon atoms. R is generally ing the prescribed nprnberof carbon atoms. R reprea branched chain alkyl radical because of the ready availice sents hydrogen or a hydrocarbyl radical having from 1 to 30 carbon atoms of the same types defined for R.

Examples of effective amines include laurylamine, tridecylamine, tetradecylamine, hexadecylamine, octadecylamine, eicosylamine, tricosylamine, noncosylamine, nonylphenylamine, dodecylphenylamine, methyldodecylamine, dimethyldodecylamine, methyloctadecylamine, and dimethyloctadecylamine. Particularly preferred amines are certain commercially available mixtures of tertiary alkyl primary amines. For example, a mixture of tertiary alkyl primary amines in which the alkyl radical comprises a mixture of alkyl groups having from 11 to 14 carbon atoms is available under the name Primene 81-R. Another commercially available amine is the mixture of tertiary alkyl primary amines in which the alkyl radical comprises a mixture of alkyl groups having 18 to 24 carbon atoms sold under thename Primene JM-T.

The Schiff base which which corresponds to the formula:

H RIIN ORI in which R and R have the values noted above and which is employed to form the adduct of the invention is prepared from an amine and an aldehyde. Specifically, equivalent amounts of a primary amine and an aldehyde are contacted either in the presence of or without a solvent. The reaction frequently occurs spontaneously although at times moderate heating is required. A mole of water splits out in the formation reaction of the Schifi base. The water formed by the reaction is generally removed by azeotroping with a solvent, such as toluene. It is essential that the sum of the carbon atoms represented by R' and R in the formula for the Schiff base amount to at least 12 in order to insure the oil solubility of the'adduct that is to be formed.

Amines which can be employed to prepare the Schiff base are the primary aliphatic amines. These amines are represented by the following formula:

in which R is an aliphatic hydrocarbyl radical having from 1 to 30 carbon atoms. The preferred amines are those in which R is a branched chain alkyl radical having from about 12 to 24 carbon atoms.

Examples of suitable primary amines for the Schilf 'base reaction include butylamine, amylamine, hexyla- R'CHO in which R is hydrogen or a hydrocarbyl radical having from 1 to 30 carbon atoms. The hydrocarbyl radi- .cal can be an aliphatic or an aromatic hydrocarbyl radical and preferably has from 1 to 10' carbon atoms. EX- amples of effective aldehydes for this reaction include formaldehyde, 2-ethylhexaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, nonylaldehyde, palmitaldehyde, lauraldehyde, stearaldehyde, benzaldehyde and salicylaldehyde.

The adducts of the invention are prepared by mixing from 1 to 6 moles, preferably 1 to 4 moles, of a hydrocarbyl amine or a Schiif base defined above with a mole of zinc silicofluoride, zinc phosphite, zinc hypophosphite, zinc sulfite or zinc thiocyanate. This reaction is usually exothermic and provision must generally be made to cool the reaction mixture. In particular, caution must be exercised to keep the reaction temperature below the decomposition temperature of the various components of the reaction product or adduct which generally means conducting the reaction at a temperature below about 200 C. The reaction generally goes to completion in a short reaction time.

The reaction of a zinc compound with an amine or a Schilf base to form the adduct of the invention is unpredictable. Many zinc compounds do not form adducts with either the amines or Schitf bases. For example, zinc fluoride, zinc borate, zinc sulfate, zinc sulfide'and zinc oxide would not form adducts with the amines or Schiflf bases.

Examples of adducts of the invention are given below. For convenience, the Schifi? base part of the adducts listed is expressed in terms of the components from which the Schiff bases are formed. The mole ratio in parenthesis is the ratio of the amine or Schifi base to the zinc compound.

Primene JM-Tzzinc sulfite (4:1)

' Primene JM-Tzzinc phosphite (2:1)

Primene JM-Tzzinc phosphite (1:1)

Primene JM-T2zinc silicofluoride (2: 1)

Primene J M-T:zinc thiocyanate (2:1)

Primene JM-T2zinc hyp-ophosphite (3: 1)

Primene 81-Rzzinc silicofluoride (2:1)

Primene 81-Rzzinc thiocyanate (2:1)

Primene JM-T/formaldehydezzinc phosphite (2:1) Primene JM-T/Z-ethylhexaldehyde:zinc thiocyanate (2:1), and Primene JM-T/Z-ethylhexaldehyde:zinc silicofluoride The lubricating composition of the invention is prepared by blending in a conventional way a minor amount of the oil-soluble, load-carrying hydrocarbyl amine or Schiff base zinc compound adduct described hereinabove into a suitable lubricating oil base. Generally, the adduct is employed in an amount in the range of 0.05 to percent by weight based on the weight of the lubricating composition with the preferred proportions of the adduct being from 0.1 to 3 weight percent.

The base lubricating oil can be a mineral lubricating oil or a synthetic lubricating oil. The mineral lubricating oil can be a predominantly paraflinic or naphthenic oil or can be a mixture of the two types of mineral oils.

Generally, the mineral oil will be a refined oil of predominantly parafiinic nature, having a viscosity in the range from 30 to 150 Saybolt Universal seconds at 210 F.

Various types of synthetic lubricating oil bases can be employed in preparing the lubricants of the invention. Aliphatic ester, polyalkylene oxides, silicones, esters of phosphoric and salicylic acid and the highly fluorine-substituted hydrocarbons can be employed. Examples of the aliphatic esters include di-(2-ethylhexyl) sebacate, the dialkyl azelates, dialkyl suberates, and the dialkyl adipates such as di-hexyl azelate, di-(Z-ethylhexyl) azelate, di- 3,5,5-trimethylhexyl gluterate, di-(Z-ethylhexyl adiphate, triaimyl tricarb allylate, etc. The polyalkylene oxide lubricants include polyisobutyloxide, polyisopropylene oxide diether, polyisopropylene oxide diesters, etc. The silicone lubricants include methyl silicone, methylphenyl silicone and the silicate lubricants include tetraisooctyl silicate. The highly fluorinated hydrocarbon lubricants include TAB LE I.L OAD .4 fluorinated oil, perlluorohydrocarbons and the like.

Other effective synthetic lubricating oils include the neopentyl glycol esters such as the neopentyl glycol propionates, neopentyl glycol butyrates and the neopentyl glycol caprylates and the trimethylol alkanes such as trimethylolethane, trimethylol propane, trimethylol pentane, trimethylol heptane and trimethylol dodecane and the like. Examples of the phosphate esters include tricresyl phosphate, trioctyl phosphate and.tridecyl phosphate as well as mixed aryl and alkyl phosphates.

Example I The load carrying and anti-scuff properties of lubricating compositions of the invention were determined in a number of standard tests. The Mean Hertz Load Test is run in a machine having four inch diameter bearing balls which are driven under load while being lubricated by the composition under test. The description of this test is set forth in US. Patent 2,600,058.

In the Ryder Gear Test (Federal Test Method 6508), the lubricant being tested is employed to lubricate two spur gears in a Pratt and Whitney Gear and Lubricating Tester. This tester was operated with a gear speed of 10,000 rpm. and with an oil inlet temperature of 165 F. The loading pressure of 5.0 p.s.i. was applied during break-in. After 10 minutes the tester was shut down and the gear examined for the percentage of tooth area scuff on each tooth. This procedure was repeated using a high load pressure with increments of 5 psi. until 22.5 percent of the total tooth area on the driving gear had been scuffed, the load applied in this run being considered the scuif load. The tooth load in pounds per inch of tooth width was then calculated.

The Navy Four Ball Wear Test also measures the anti-wear properties of a lubricant. The test machine employed comprises a system of four steel balls, three of which are in contact with each other in one plane in a fixed triangular position in a reservoir containing the oil sample and a fourth ball is above and in contact with the other three. In carrying out the test, the upper ball is rotated at a speed of 1800 rpm while it is pressed against the lower three at a constant load of.28 kg. for four separate periods of 10, 40, and minutes. The wear rate is calculated in microns per minutes.

The Mean Hertz Load was determined by means of the same equipment used in the Navy Four Ball Wear Test, using Federal Test Method Standard 791A, Method 6503.

Lubricating compositions illustrative of the invention were prepared from both mineral and synthetic lubricating oils. The mineral lubricating oil was essentially a paraffinic lubricating oil having an SUS viscosity at 210 F. of about 100. This is designated as Base Oil A. The synthetic lubricating oil consisted of di-2-ethylhexyl sebacate plus sebacic acid. This oil, which is commercially available as Plexol 201], is designated as Base Oil B in the example. The adduct mole ratio indicated in parenthesis is the mole ratio of the hydrocarbylamine or of the Schiff base employed to the zinc compound. Schifi Base A was formed by reacting a mole of Primene JM-T with a mole of Z-ethylhexaldehyde. The test results are given in Table I below.

CARRYING AND ANTI-SCUFF PROPERTIES Navy Adduct (Mole Ratio) Percent Base Ryder Gear Mean Hertz Four Ball By Wt. 011 Test, p.p.i. Load Wear Test,

micron/min.

None I A Primene JM-T/ZnHPOg (3: 1) 1. 0 A Primene .TM-T/ZnSiF (2:1)- 1. 0 A Primene .TM-T/ZnSiFt (2: 1) 2. 0 A Schifis Base A/ZnHPOa (4:1)" 1. 0 A Sehifis Base A/Z11(SON) (2:1) 1. 0 A Primene .TM-T/ZMSCN): (2:1) 1.0 A Primene .TM-T/ZnSOa (4:1) 1. 0 Primene JM-T/ZnHPOa (2:1) 0.5 A None B Primene JM-T/ZnSiF (2:3) l. 0 B

The lubricating compositions containing the abovedescribed amine or Schiff base-zinc compound adducts have markedly improved load-carrying, wear and antiscuff properties. They also exhibit good corrosion resistance, oxidation resistance and storage stability. 'I hese valuable properties make the lubricants of the invention suitable for a broad range of lubrication applications.

It is understood that the lubricating compositions of the invention can contain numerous additives conventionally used to improve the properties of lubricating oils. Commonly employed additives are the methacrylates as V1.

improvers and pour point depressors, the alkylphenols as 7 RR N and RIIN C R! in which R is an alkyl radical having from 6 to 30 carbon atoms, R is selected from the group consisting of a hydrogen and an alkyl radical having from 1 to 30 carbon atoms and R" is an alkyl radical having from 1 to 30 carbon atoms, the sum of the carbon atoms in the compound represented by (a) and (b) being at least 12, with a mole of a zinc compound selected from the group consisting of zinc silicofluoride, zinc phosphite, zinc hypophosphite, zinc sulfite and zinc thiocyanate.

2. A composition according to claim 1 in which said zinc compound is zinc silicofluoride.

3. A composition according to claim 1 in which said zinc compound is zinc phosphite.

4. A composition according to claim 1 in which said zinc compound is zinc hypophosphite.

5. A composition according to claim 1 in which said zinc compound is zinc sulfite.

6. A composition according to claim 1 in which said zinc compound is zinc thiocyanate.

7. As a new composition, the product produced by reacting 4 moles of a C1844 alkyl primary amine with a mole of zinc silicofluoride.

8. As a new composition, the product produced by reacting 4 moles of a Schifi base with a mole of zinc phosphite, said Schiff base being obtained by reacting a mole of a C1844 alkyl primary amine with a mole of 2-ethy1- hexaldehyde.

9. As a new composition, the product produced by reacting 2 moles of a Schiff base with a mole of zinc thiocyanate, said Schiff base being obtained by reacting a mole of a C alkyl primary amine with a mole of Z-ethylhexaldehyde.

10. A lubricating composition comprising a major proportion of a lubricating oil and 0.05 to 10 percent by Weight of an oil-soluble composition produced by reacting 1 to 6 moles of a compound represented by a formula selected from the group consisting of:

(a) RR N and in which R is an alkyl radical having from 6 to 30 carbon atoms, R is selected from the group consisting of hydrogen and an alkyl radical having from 1 to 30 carbon atoms and R is an alkyl radical having from 1 to 30 carbon atoms, the sum .of the carbon atoms in the compound represented by (a) and (b) being at least 12, with a mole of a zinc compound selected from the group consisting of zinc silicofluoride, zinc phosphite, zinc hypophosphite, zinc sulfite and zinc thiocyanate.

11. A lubricating composition according to claim 10 in which said oil-soluble compound is the product produced by reacting 4 moles of a C1844 alkyl primary amine with a mole of zinc silicofiuoride.

12. A lubricating composition according to claim 10 in which said oil-soluble compound is the product produced by reacting 4 moles of a Schitf base with a mole of Zinc phosphite, said Schiit base being obtained by reacting a mole of a C alkyl primary aminne with a mole of Z-ethylhexaldehyde.

13. A lubricating composition according to claim 10 in which said oil-soluble compound is the product produced by reacting 2 moles of a Schitf base with a mole of. zinc thiocyanate, said Schiff base being obtained by reacting a mole of a C1844 alkyl primary amine with a mole of Z-ethylhexaldehyde.

References Cited by the Examiner UNITED STATES PATENTS 2,112,567 3/1938 Havas 260--429.9 2,725,358 11/1955 Kluge et al 252-42.7 3,107,739 10/ 1963 Mathews 260429.9

DANIEL E. WYMAN, Primary Examiner.

L- G- X L R. 0S v As i tant Exam ner, 

10. A LUBRICATING COMPOSITION COMPRISING A MAJOR PROPORTION OF A LUBRICATING OIL AND 0.05 TO 10 PERCENT BY WEIGHT OF AN OIL-SOLUBLE COMPOSITION PRODUCED BY REACTING 1 TO 6 MOLES OF A COMPOUND REPRESENTED BY A FORMULA SELECTED FROM THE GROUP CONSISTING OF: (A) RR''2N 